“They have understood the value of having a strong brand, a corporate identity that people can engage with.”

As a terror group, Isis is at the forefront of media technology in its bid for new recruits and even developed an app called “Dawn of glad tidings” through Google Play for Android phones.

Once downloaded, the app effectively hijacked the phone to distribute official Isis tweets and images to Twitter accounts, according to Channel 4 News.

It was sophisticated enough to get around most spam detectors and was designed to have its messages Trending on Twitter.

It was finally stopped when Google took it down.

Followers have also used other social media websites like Ask-fm to provide tips and advice on how to join the fight.

In its 400-page annual report for 2013, Isis claimed to have carried out more than 7,600 operations in Iraq, including 1,000 assassinations and planting more than 4,400 roadside bombs.

It also claims to have assassinated 1,083 people and conducted 607 mortar attacks.

Like any corporate document, it uses computer-generated graphics and lists its targets and performance – but in relation to death and carnage.

Concerns about the strength and sustainability of Isis have deepened in recent days amid fears its has raided banks in the Iraqi cities it took over, looting hundreds of millions of pounds in the process.

Jessica Lewis, director of research at the Institute for the Study of War, said: “They have a business plan and their principal business is expansion through conquest.

“It is a very effective institution and that makes for a very effective military national corporation.”

Messages from apparent British jihadists show they are already under the influence of Isis and its leader Abu Bakr al-Baghdadi.

One said he had ordered his followers to "go back" to Britain.

It said: "@AbuRashashISIS: @AbuHussain101 I my brother intend to go back to #UK under the order of our Ameer Abu Bakr Al-Baghdadi #foreign policy,".